Commercial paging has been in use for many years to deliver short text or numerical messages to people who do not need to provide an immediate response. Repair crews, security guards, nurses and medical staff are typical users of wireless paging. Hospitals extensively use wireless paging to deliver emergency and mission critical messages to medical staff that simply require a message instruction to act immediately. In order to shorten the delivery time of critical messages, hospitals normally install on-site messaging systems that are especially made to deliver messages in a few seconds rather than minutes as is typical when using a commercial paging or other messaging service.
Conventions used by operators of two-way portable radios or on-site wireless telephones are meant to ensure that the receiver of a message provides feedback to the sender in the form of a spoken statement. These communications devices are typically larger and more expensive than pagers because they require hardware such as a microphone and a transmitter for effecting the two-way conversations. Furthermore, in environments such as hospitals, where messages need to be transmitted for the purposes of alerting the staff to emergencies and the like, two-way radios and on-site wireless telephones are of limited use because they do not have the facility to store a message for the receiver in case the receiver is too busy to vocally respond. In addition, FCC (Federal Communications Commission) and government communications agencies around the world do not typically approve of the use of commercial wireless telephones in hospitals due to possible interference with medical equipment.
The type of messages that are typically received by a pager or similar portable device are short text messages. These messages are often telephone numbers where the caller can be reached, or short text instructions. One of the assets of the pager lies in its ability to receive instruction messages of the type that do not require responses. Hospitals make use of on-site paging systems to immediately alert staff of emergency events such as a patient pressing a button in their room, a heart attack situation, urgent aid required, scheduled medicine administration, and all sorts of emergency and staff-to-staff communication needs. The benefit of an onsite messaging system capable of delivering immediate messages from telephones, network computers or stand-alone entry devices without having confirmation that the message was actually received can be greatly affected when the system itself can not confirm that the message was transmitted over the air and that the destination device received the message. For instance, hospital on-site paging systems are open-looped, but can have, by nature of typical hardware, many potential points of failure. Transmitters, for example, which are often situated on the roof of a building, are subject to weather hazards, and computers running such a system can crash as a result of various factors.
One of the key problems that results from using open-loop on-site paging and other messaging systems in general, is that no corrective action or administrator notification is effected at the time when a system failure occurs. Steps are taken only after someone complains that a message was not responded to, at which point several important messages could have been lost. This situation is unacceptable when messages are sent in connection with hospital emergencies and other critical instances in which speed of response is vital to the situation.